WASHINGTON — This week’s news that Representative George Miller, Democrat of California, is planning to retire at the end of the year reverberated around the House of Representatives, where Mr. Miller has served since 1975.

But the news hit even harder around another less stately, more fratlike house about a quarter-mile southeast of the Capitol, where Mr. Miller has lived for more than 30 years with a rotating cadre of congressional Democrats — and which served as the inspiration for the Amazon web series “Alpha House.”

Mr. Miller, 68, who owns the two-story, two-bedroom house — part messy crash pad, part political seminar — currently shares it with Senators Richard J. Durbin of Illinois, the majority whip, and Charles E. Schumer of New York, the No. 3 Democrat …